Image.filename is not an exposed property

[bburtin]

The Pillow reference says that Image.filename is an attribute, but VSCode doesn't auto-complete it. This code works:

but VSCode shows image.filename as white whereas the other attributes are blue. Is it possible to make Image.filename a declared Python attribute so that developers have confidence that their code will work?

I'm using Pillow 10.3.0.

[nulano]

From https://pillow.readthedocs.io/en/stable/reference/Image.html#PIL.Image.Image.filename:

Only images created with the factory function open have a filename attribute.

We currently do not have a way to distinguish how an Image was created via a type hint, so there is no simple way to add a type hint for the attribute AFAIK.

Edit: Although PIL.Image.open returns a PIL.Image.Image according to the type hint here

Pillow/src/PIL/Image.py

Line 3225 in e8ab564

def open(fp, mode="r", formats=None) -> Image:

as well as in typeshed, perhaps we should consider changing that to PIL.ImageFile.ImageFile since (based on a quick search) all of the existing image plugins seem to use that as their base class.

[bburtin]

Thanks for the fast response! It's not possible to declare the Python property as str | None and only set it when Image.open() is called?

[nulano]

Declaring filename: str | None implies that image.filename will not raise an AttributeError as it currently does:

>>> from PIL import Image
>>> Image.new("RGB", (10, 10)).filename
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AttributeError: 'Image' object has no attribute 'filename'

[radarhere]

perhaps we should consider changing that to PIL.ImageFile.ImageFile since (based on a quick search) all of the existing image plugins seem to use that as their base class.

The factory that Image.open uses is already hinted to return ImageFile.ImageFile, so yes, this makes sense.

Pillow/src/PIL/Image.py

Line 3298 in e8ab564

factory, accept = OPEN[i]

Pillow/src/PIL/Image.py

Lines 222 to 228 in e8ab564

	OPEN: dict[
	str,
	tuple[
	Callable[[IO[bytes], str | bytes], ImageFile.ImageFile],
	Callable[[bytes], bool] | None,
	],
	] = {}

I've created #7943

[nulano]

And I've just created #7944 to the the same thing, as well as add type hints for the Image.open parameters. 😄